Hello...I am ready to drill the hole and destroy as much of my filter as I can. Could you tell me how precise I need to be with location? I saw that here the washer needed to be ground, so can we Drill in the flat area? Let me know what you think. Thanks!

Any chance you could help me with where to actually drill the hole? How precise do we need to be....? I’m hoping my 2001 XC70 can be revived. I’ve changed the solenoids and then the entire valve body, but am realizing the problem all along was the filter....